1. Field Of The Invention
This invention relates to computer circuitry and, more particularly, to apparatus and a method for assuring that an application program which is run on a computer is authorized to run on such circuitry.
2. History Of The Prior Art
If an application program is to be executed by a computer, it must be read into the computer's memory from whatever medium (e.g., floppy disk or CD-ROM) was used to supply it to the user. If the application is read into memory it can normally be written to some other storage medium. Since application programs are copyable, anyone who has purchased an application program may copy that program for use by someone else. Because of this, the manufacture and sale of software for personal computers are especially subject to fraud.
There have been various attempts to stop copying in the personal computer industry by varying the format by which an application is placed on the media so that the data cannot be copied using standard utility programs. However, application programs on magnetic media may be easily destroyed or damaged; and buyers are generally unwilling to spend significant sums for any application program which they cannot back up so these attempts have been commercially unsuccessful.
To stop illegal use of software used on workstations, manufacturers have assigned unique numbers to each workstation and prepared a password for each physical piece of software authorized to be used on a particular workstation. When an authorized program is run on a workstation, the value of the password is tested against the workstation number by a software process within the application program, and if the values check; the machine operates. When the values do not check, something undesirable from the standpoint of the operator occurs. This method of monitoring against unauthorized use has cut down the illegal use of software on workstations. However, it is not too difficult to modify the software of the application program so that it will run on a workstation even though the workstation is numbered incorrectly for the particular password. Typically, portions of the copied program which would invoke the check of password against machine number are simply removed from the program.
Unfortunately, personal computers are not equipped with unique identification numbers; and there is presently no useful system in effect for curtailing the use of copied software. Moreover, even were the workstation system of checking to be utilized, it is sufficiently easy to work around that it would only slow the fraudulent use of software for a period until the methods for defeating the safeguard had been passed around to the various computer bulletin boards.
It is very desirable to provide apparatus and a method of reducing the risk that personal computer software which may be copied may then be used without authorization of the manufacturer.